2019 Volume 19 Issue 4 Pages 4_122-4_155
It was proposed to compile knowledge related to the broad-based crustal structure boundaries of the eastern margin of the Japan Sea obtained so far and to study uncertainties concerning the rupture zone and earthquake magnitude, and multi-segment earthquake. For that study, the crustal structure boundaries are set as the first branch to determine a logic tree for evaluation of epistemic uncertainties for tsunami estimation in the area. Moreover, the tsunami source models of the crustal structure boundary type were presented as one of the definite models that are necessary to evaluate the uncertainties. These tsunami source models are models exceeding the magnitude of the previous ones. They were developed for the region of which east dipping reverse faults were confirmed continuously by exploring the crustal structures concerning the nascent plate boundary theory, previous knowledge of the strain concentration zone, and latest finding on the crustal structure boundaries were compiled for development of the models. The assumable earthquake magnitudes are Mw 7.7 to 8.6, which exceed the magnitudes (Mw 7.5 to 7.9) of the crustal earthquakes of the tsunami source models of Ministry of Land, Infrastructure, Transport and Tourism (2014). Furthermore, the numerical simulation of tsunami propagation was performed using the tsunami source models of crustal structure boundary type and the crustal earthquake type to confirm the effect of the tsunami water level in the Japan Sea coast area. The results showed that the tsunami water levels obtained by the crustal structure boundary type models were two to three times higher than that by the crustal earthquake type models. Furthermore, the regional differences of the maximum water level were emphasized more by the crustal structure boundary type models than the crustal earthquake type models.
